Why has spacetime torsion such negligible effect on our universe?

TL;DR

This paper explains why spacetime torsion has negligible effects in our universe by proposing a warped extra dimension with a Kalb-Ramond field, leading to exponential suppression of torsion effects in four dimensions.

Contribution

It introduces a model with a warped extra dimension and a Kalb-Ramond field that naturally suppresses torsion effects in our four-dimensional universe.

Findings

Exponential suppression of the KR field on the visible universe.

Back reaction from radius stabilization enhances torsion suppression.

Warped extra dimension explains negligible torsion effects.

Abstract

We attempt an answer to the question as to why the evolution of four-dimensional universe is governed by spacetime curvature but not torsion. An answer is found if there is an additional compact spacelike dimension with a warped geometry, with torsion caused by a Kalb-Ramond (KR) antisymmetric tensor field in the bulk. Starting from a Randall-Sundrum type of warped extra dimension, and including the inevitable back reaction ensuing from the radius stabilization mechanism, we show that there is always an extra exponential suppression of the KR field on the four-dimensional projection that constitutes our visible universe. The back reaction is found to facilitate the process of such suppression.